On limited-access highways, which units should proceed directly to the scene of an emergency?

The primary or first-due units are the first responders that arrive at the scene of an emergency on limited-access highways. These units are specifically trained and equipped to handle the initial assessment and response to incidents, which may include traffic collisions, medical emergencies, or hazardous material incidents. Their primary objective is to ensure safety, control the situation, and provide necessary assistance to victims.

These first-due units have the expertise required to effectively manage the immediate needs of the scene, including securing the area, providing medical aid, and initiating any required extrication processes. They often work in coordination with dispatch and other responding agencies to ensure a comprehensive response.

In contrast, secondary or third-due units, support, and backup units typically have roles that involve providing additional resources, handling traffic control, or aiding with logistical support after the primary units have assessed the situation. All available units would not proceed directly to the scene as it could lead to unnecessary congestion and hinder the initial response. Therefore, the focus is rightly placed on the primary or first-due units for immediate intervention in emergency situations on limited-access highways.